Next generation graphene-based biosensor for the fast detection of xanthine

Xanthinuria is a rare disease caused by the accumulation of xanthine in blood, which can lead to serious pathologies, such as renal failure or gout.

ICMAB researchers have prepared a novel hybrid graphene-based electrochemical biosensor for the fast and 100 times more sensitive detection of xanthine, with respect to previously reported sensors.

The study, published in the journal Advanced Materials Interfaces, combines the properties of reduced graphene oxide and those of the organic radicals to prepare next generation, low cost electrochemical biosensors.

Xanthine, which is an organic molecule found in most human body tissues and fluids, is a methabolic product on the pathway of purine degradation, and is converted to uric acid by the action of the xanthine oxidase enzyme.

Xanthinuria, also known as xanthine oxidase deficiency, is a rare genetic disorder that appears when there is an excess of xanthine in serum. This can lead to serious pathologies such as renal failure or gout. Therefore, fast and sensitive diagnosis methodologies for determining xanthine at very low concentrations are crucial.

In this work, published in Advanced Materials Interfaces, a group of ICMAB researchers lead by Dr. Núria Crivillers, have prepared a hybrid material, based on reduced graphene oxide modified with a stable organic radical, to exploit both the antioxidant activity of the reduced graphene oxide and the electrochemical reactivity of the organic radical towards superoxide anion radical (O2·-), which is derived from the xanthine/xanthine oxidase enzymatic system.

The novel electrochemical biosensor enables the detection of xanthine with a decreased detection limit 100 times with respect to previously reported sensors. Moreover, this graphene-based biosensor can overcome the limitations of the current methods, which are usually expensive, complicated and time consuming, thanks to its simplicity, rapidness, sensitivity, specificity and low cost.

Figure:Scheme and electron microscopy image of the graphene-based biosensor. The superoxide anion radical is formed when xanthine is converted to uric acid by the action of xanthine oxidase. Red color for carbon; green for chlorine.